The present invention relates to a method for producing negatively charged oxygen atoms and an apparatus for producing negatively charged oxygen atoms which may be employed for the aforementioned method. Negatively charged oxygen atoms are represented by O−and come in very useful in various fields, for example, for oxidative reaction in gaseous phase, fabrication of silicon oxidized film in semiconductor manufacturing process, mildew-proof treatment of fruits such as strawberries, maintaining sea food freshness such as maintaining tuna freshness.
As a method for producing negatively charged oxygen atoms, it is known to bring low-energy electrons to adhere to oxygen atoms generated by electric discharge and the like, thereby producing negatively charged oxygen atoms. However, this method has a problem that high vacuum is required for causing electric discharge and a problem in view of energy.
Another known method is a method in which ozone is generated by electric discharge in an oxygen gas, the resulting ozone is irradiated with ultraviolet rays, whereby low-energy electrons adhere to the resulting oxygen to produce negatively charged oxygen atoms (JP62237733A). However, this method has a problem that a large quantity of discharge energy is required for generating ozone.
The present invention aims to provide a method and an apparatus for effectively producing negatively charged oxygen atoms without requiring such high vacuum and such discharge energy.